The present invention relates to a technology of transferring a file between storage devices such as magnetic-disk devices and opto-magnetic-disk devices. More particularly, the present invention relates to a technology of directly transferring a file between storage devices.
Generally employed as an external storage device of a host computer, a magnetic-disk device and an opto-magnetic-disk device can each be used for storing a large amount of data. These storage devices normally include an embedded processor for carrying out advanced information processing. However, the processing carried out by the embedded processor is limited to a range for executing control of internal operations on the basis of instructions received from a host computer in a passive manner. When a storage device is replaced due to device aging or another reason, it is necessary to copy data stored in the storage device being replaced to another storage device. In this case, it is necessary to execute a procedure for once transferring the data stored in the storage device being replaced to a host computer and then transferring the data from the host computer to the other storage device. Such a procedure entails the use of host-computer resources such as a CPU, a memory, and a bus. In addition, the user must bear a heavier burden such as the need to operate the host computer and consideration to prevent a trouble from being generated in the entire system of the host computer.
Moreover, during a time period between completion of the assembly of the storage device at the manufacturing stage and a state in which the storage device can be shipped to the user as a complete product, it is necessary to carry out a large number of optimization and inspection processes such as adjustments, optimizations of parameters, and/or inspections. Traditionally, special test apparatus are used for carrying out the optimization and inspection processes. However, production of such storage devices in volume in accordance with this method raises problems that a large investment in the test apparatus is required and the time it takes to carry out the optimization and inspection processes becomes longer.
Japanese Patent Laid-open No. 2003-15782 discloses a technology providing a first operating mode and a second operating mode. The first mode allows an electronic apparatus to function as a host, and the second operating mode allows the electronic apparatus to function as a peripheral. In accordance with a determination result produced by a determining means for determining the type of a power supply connected to the electronic apparatus, the first operating mode is inhibited. The inhibition is in order to prevent the electronic apparatus from entering a state of being incapable of functioning right after the start of the electronic apparatus to function as the host.
Japanese Patent Laid-open No. 2000-347816 discloses a technology of using a multi-communication line or a switch for connecting a loop control unit to magnetic-disk devices. In an environment providing a configuration wherein each of the magnetic-disk devices is capable of operating as an SCSI target or initiator, data is transferred among the magnetic-disk devices. With this technology, a control apparatus is capable of carrying out processing based on a request received from a host computer even while data is being transferred among the disk devices. This patent document describes the fact that a specific magnetic-disk device receives a command from the loop control unit to operate as an initiator. However, this patent document includes neither concrete description revealing how data can be transferred to another magnetic-disk device nor concrete method for switching a magnetic-disk device from the function of a target to that of the initiator in order to transfer data. In addition, the data transfer described in the patent document is carried out in accordance with a command received from a host apparatus such as the loop control unit in an environment connecting the magnetic-disk devices to the host apparatus.